In the prior art, the wire connecting box of a lamp is locked to a retaining block. The center of the block has a hole. A threaded tube is locked to the retaining block. The threaded tube passes through a hole in the retaining block. Then the threaded tube is fixed by screwing with a male nut so that the retaining block will not fall down. A lower side of the retaining block is fixed with a hanging ring so that a lamp can be suspended from the ring. Thereby, the buckling block can load the lamp. However, above prior art has the following defects. Firstly, the prior art retaining block is made of iron which is cheap, but weak. It is often that after it is used for a time period, the retaining block cracks and thus is dangerous. Moreover, in assembly, the lamp is heavy and much labor is necessary in assembly. Thus the cost is high and the operation is inconvenient.